For the past six months i have been working on a short documentary which follows the University of Utah Quidditch team. We just released the trailer for the film which will premier this November at the Rose Wagner theater along with 3 other student produced films.
They are serious. It is actually pretty rough. At the tournament the team actually had one player knocked out, a broken ankle and a whole bunch of other minor injuries. Don't knock it till you've tried it.
Just because it's serious doesn't mean it counts as a physically intensive sport. I mean, how fast can you really run while holding a broom between your legs? Even though you can get hurt it doesn't mean it's a crazy sport, it could just be kids tripping over their brooms into one another.
I'd rather do LARPing. IF they made a quidditch "inspired" game I might say OK, but running with a broom serves no purpose and is just dumb. But hey, each to their own, it amuses the people who play and everyone else who sees it, so I guess its a win win.